Candidate's Background. As a global health researcher who specializes in the sociocultural dimensions of sexual health in Latin America, is fully bilingual and has lived and worked in Peru for the past eight years, I am in a unique position to make significant contributions to the prevention of HIV and other sexually transmitted infections (STIs) in Peru and in the region. I am currently a Postdoctoral Fellow in Global AIDS Prevention Research at the University of California, Los Angeles Program in Global Health, based in its Peru office. I have a strong interest in how to combine research and public health interventions to prevent HIV/STIs. However, I need additional training and mentorship to strengthen my skills in the development and assessment of global HIV/STI prevention interventions. The International Research Scientist Development K01 Award (IRSDA) would enable me to obtain this training and carry out mentored research to implement and assess a pilot HIV/STI prevention intervention with male sex workers or fletes in Peru. 2. Career Goals and Objectives. My long-term objective is to become a successful independent investigator who makes significant contributions to research and public health by developing, implementing and assessing rigorously evaluated, innovative HIV/STI prevention interventions in Peru and Latin America. I will achieve this objective by meeting these goals during the award period: 1. Complete academic training in: (1) key issues in HIV/STIs and global health; (2) social and cultural forces around sex work; (3) sampling methods with hidden populations; (4) design, implementation and assessment of biomedical, behavioral, and combination trials for HIV/STI prevention; (5) analysis of multi- component HIV/STI prevention trials; and (6) responsible conduct of research. 2. Complete the proposed Research Plan, described in the last section below (section 5). 3. Present the results from my IRSDA research at international scientific meetings. 4. Publish at least 6 peer-reviewed articles from my IRSDA research. 5. Develop and submit an NIH R01 proposal to implement a randomized controlled trial of a comprehensive intervention for fletes in Peru, to be developed based on the findings from this IRSDA proposal. 3. Mentoring Team. My mentors and co-mentors are leaders in the field of HIV/STI prevention and will provide intensive guidance during the IRSDA period. Dr.Thomas Coates, Professor and Director of the Program in Global Health (PGH) at the University of California, Los Angeles (UCLA), is my U.S.-based mentor. Dr. Patricia Garcia, Professor at the Universidad Peruana Cayetano Heredia (UPCH) School of Public Health, is my Peru- based mentor. Dr. Martin Iguchi from Georgetown University, Dr. Pamina Gorbach from UCLA, and Dr. Deanna Kerrigan from the Johns Hopkins Bloomberg School of Public Health will serve as co-mentors. 4. Institutional Environments. UCLA is home to global HIV-related research centers including the PGH, directed by Dr. Coates. PGH has conducted several global HIV prevention projects that include Comunidades Positivas, an ongoing community-level HIV/STI prevention trial in low-income, urban Peru where communities are randomized to a behavioral intervention, a biomedical intervention, or both. PGH has an office in Peru to support investigators working in Latin America. UPCH has an impressive track record in internationally-funded research, including in HIV/STIs. The Unit of Epidemiology, STDs and HIV, directed by Dr. Garcia, has full-time research and support staff, office space, a Data Management and Analysis Center, and an STI Laboratory. The Unit has carried out several large studies on HIV/STI prevention in Peru and is currently implementing Brighter Futures, to develop and apply diagnostic tests - including for STIs - for maternal and child health. My K01 will benefit from the infrastructure and lessons learned during Dr. Coates' and Dr. Garcia's studies. 5. Research Plan. The overall aim of the proposed study is to implement and assess a pilot Skill-building Program intervention that will provide fletes with vocational training and HIV/STI prevention skill-building within a supportive environment in order to prevent HIV/STIs in this group. Studies demonstrate that HIV/STIs disproportionately affect men who have sex with men (MSM) in Peru, with HIV seroprevalences among MSM ranging from 17.8-22.3% and recent syphilis infection of 10.5% among men who have sex with only men. Dr. Coates, Dr. Garcia and I carried out formative research, which demonstrated that fletes are a critical component of the Peruvian HIV epidemic, with high prevalence of both HIV (23%) and syphilis (22%). Therefore, this proposal aims to implement and assess a pilot Skill-building Program to prevent HIV/STIs among fletes. The Specific Aims are as follows: (1) To develop an ethnographic map of flete-related sex work venues and enumerate the fletes present in each venue; (2) To develop the assessment survey for the Skill- building Program intervention; and (3) To estimate the effectiveness of the pilot Skill-building Program for reducing (a) the proportion of fletes' income that is derived from sex work, (b) the proportion of fletes who report unprotected intercourse with clients, and (3) incidence of HIV and syphilis among fletes.